{- git-annex command
 -
 - Copyright 2015 Joey Hess <id@joeyh.name>
 -
 - Licensed under the GNU GPL version 3 or higher.
 -}

module Command.Smudge where

import Command
import qualified Annex
import Annex.Content
import Annex.Link
import Annex.FileMatcher
import Annex.Ingest
import Logs.Location
import qualified Database.Keys
import Git.FilePath

import qualified Data.ByteString.Lazy as B

cmd :: Command
cmd = noCommit $ noMessages $
	command "smudge" SectionPlumbing 
		"git smudge filter"
		paramFile (seek <$$> optParser)

data SmudgeOptions = SmudgeOptions
	{ smudgeFile :: FilePath
	, cleanOption :: Bool
	}

optParser :: CmdParamsDesc -> Parser SmudgeOptions
optParser desc = SmudgeOptions
	<$> argument str ( metavar desc )
	<*> switch ( long "clean" <> help "clean filter" )

seek :: SmudgeOptions -> CommandSeek
seek o = commandAction $
	(if cleanOption o then clean else smudge) (smudgeFile o)

-- Smudge filter is fed git file content, and if it's a pointer to an
-- available annex object, should output its content.
smudge :: FilePath -> CommandStart
smudge file = do
	b <- liftIO $ B.hGetContents stdin
	case parseLinkOrPointer b of
		Nothing -> liftIO $ B.putStr b
		Just k -> do
			-- A previous unlocked checkout of the file may have
			-- led to the annex object getting modified;
			-- don't provide such modified content as it
			-- will be confusing. inAnnex will detect such
			-- modifications.
			ifM (inAnnex k)
				( do
					content <- calcRepo (gitAnnexLocation k)
					whenM (annexThin <$> Annex.getGitConfig) $
						warning $ "Not able to honor annex.thin when git is checking out " ++ file ++ " (run git annex fix to re-thin files)"
					liftIO $ B.putStr . fromMaybe b
						=<< catchMaybeIO (B.readFile content)
				, liftIO $ B.putStr b
				)
			Database.Keys.addAssociatedFile k =<< inRepo (toTopFilePath file)
	stop

-- Clean filter is fed file content on stdin, decides if a file
-- should be stored in the annex, and outputs a pointer to its
-- injested content.
clean :: FilePath -> CommandStart
clean file = do
	b <- liftIO $ B.hGetContents stdin
	if isJust (parseLinkOrPointer b)
		then liftIO $ B.hPut stdout b
		else ifM (shouldAnnex file)
			( do
				-- Even though we ingest the actual file,
				-- and not stdin, we need to consume all
				-- stdin, or git will get annoyed.
				B.length b `seq` return ()
				liftIO . emitPointer
					=<< go =<< ingest =<< lockDown cfg file
			, liftIO $ B.hPut stdout b
			)
	stop
  where
	go (Just k, _) = do
		logStatus k InfoPresent
		return k
	go _ = error "could not add file to the annex"
	cfg = LockDownConfig
		{ lockingFile = False
		, hardlinkFileTmp = False
		}

shouldAnnex :: FilePath -> Annex Bool
shouldAnnex file = do
	matcher <- largeFilesMatcher
	checkFileMatcher matcher file

emitPointer :: Key -> IO ()
emitPointer = putStr . formatPointer